Limited accessibility to fasteners is a common problem in many industries. In the aerospace industry, the problem of limited access to fasteners may be more pronounced due to more stringent engineering requirements and the smaller space constraints associated with aerospace structures. Furthermore, a relatively large quantity of fasteners may be used in the aerospace industry as compared to other industries. For example, hundreds of thousands of fasteners may be used in a single aircraft. A fair percentage of such fasteners may be installed in areas where access is limited.
For example, many aircraft include stiffeners or stringers which may be coupled to a skin member in order to increase the stiffness of the skin member. Such stringers may include a base having a vertical web extending upwardly from the base with a lateral flange extending outwardly from the vertical web. The lateral flange may extend over a row of fasteners which fasten the base of the stringer to the skin member. Unfortunately, the lateral flange may prevent vertical access to the fastener using conventional tools such as a conventional socket wrench. The limited amount of space between the fastener and the lateral flange may also limit access to the fastener using conventional hand tools such as a conventional box end wrench or open end wrench.
Certain installations in confined spaces may limit the ability to rotate such fasteners for installation or removal of the fastener using conventional tools. For example, structure that is located on opposing sides of a fastener installation may restrict fastener rotation to a fraction of the total that is required to fully disengage a nut from a threaded stud. The limited amount of rotation may require repeated cycles of installing and removing a conventional wrench from the fastener due to the limited angle through which the nut can be rotated during each cycle. As may be appreciated, limited rotational angles may increase the amount of time required to complete fastener installations using conventional hand tools.
In efforts to improve access to such fastener installations or to reduce the amount of time required to complete such fastener installations, technicians may resort to modifying commercially available tools to fit a specific installation. Although such tools may be effective in accessing certain fastener, such modified tools may be retained by the individual technician working at the specific location and may therefore be unavailable to technicians working in other locations of the same facility. In this regard, awareness of the existence of such modified tools may be confined to the individual technician and to team members of the technician.
Although tools may be modified to improve access to fasteners with limited overhead space, other limitations associated with conventional tools may present further challenges to certain installations. For example, ratchet mechanisms commonly used in conventional hand tools possess certain drawbacks that may reduce the ability to remove or install fasteners with limited rotational space. More specifically, conventional ratchet wrenches typically comprise a ratchet and pawl arrangement wherein a pivoting pawl engages teeth formed on a ratchet wheel. Such ratchet and pawl arrangements limit rotation of the wrench to a single driving direction (e.g., for loosening or tightening a nut or bolt) and allow free rotation of the wrench in a reverse direction without the need to remove the tool from the fastener.
Unfortunately, conventional ratchet and pawl arrangements exhibit a certain amount of backlash wherein the ratchet must be rotated in the reverse direction by a minimum angular amount prior to re-engagement of the ratchet in the drive direction. For fastener installations wherein rotational access is limited, excessive backlash may minimize the effectiveness of conventional ratchet and pawl wrenches in removing or installing fasteners. Although wrenches with reduced backlash are commercially available, such wrenches are typically provided in increased thicknesses which restrict the use of such wrenches in installations where overhead access is limited.
As can be seen, there exists a need in the art for a wrench that facilitates access to fasteners installed in confined spaces. More specifically, there exists a need in the art for a wrench that provides convenient access to fastener installations in locations with limited overhead space and/or limited rotational space. Additionally, there exists a need in the art for a wrench which reduces or eliminates backlash in order to improve the effectiveness of such wrenches in fastener installations having limited rotational space. Finally, there exists a need in the art for a wrench having the above-described attributes and which is simple in construction and low in cost.